Portable lantern



FIG. 1 is a perspective view of my design;

FIG. 2 is a left view of the design of FIG. 1;

FIG. 3 is a right side view of the design of FIG. 1;

FIG. 4 is a rear view of the design of FIG. 1;

FIG. 5 is front view of the design of FIG. 1;

FIG. 6 is a top view of the design of FIG. 1; and,

FIG. 7 is a bottom view of the design of FIG. 1.

The broken lines show portions of the article which form no part of the claimed design. 

CLAIM The ornamental design for a portable lantern, as shown and described. 